This Section aims to understand the principles, and mechanisms that govern intracellular calcium signalling in glial cells and neurons. Although neurons are the central players in cellular communication and information processing in the brain, recent discoveries of glial cell types, excitability and signalling properties have shown that glial cells may play an important role in long distance signalling in the brain. Although glial cells do not show electrically excitable properties similar to neurons, they do possess a form calcium based excitability in response to activation of neurotransmitter receptors. Furthermore, most physiological processes are regulated by receptor mediated signal transduction mechanisms and in a vast majority of cases these mechanisms utilize cellular calcium signals as triggers for physiological processes. Such calcium signals have recently been recognized to have complex temporal and spatial characteristics. Oscillatory [Ca2+]i changes which propagate as calcium waves and highly localized [Ca2+]i signals have been recorded in many cells. The research focus of the Section includes studies on the signal transduction mechanisms of various receptor systems as well as the cell biology of calcium signalling in both glial cells and neurons. The objectives are to understand cellular processes that control signal transduction mechanisms for Ca2+ signalling and cellular processes that regulate temporal and spatial signalling, at the molecular level.